/*
  KeePass Password Safe - The Open-Source Password Manager
  Copyright (C) 2003-2016 Dominik Reichl <dominik.reichl@t-online.de>
  
  Modified to be used with Mono for Android. Changes Copyright (C) 2013 Philipp Crocoll

  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2 of the License, or
  (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/

using System;
using System.Diagnostics;
using System.Security;

#if !KeePassUAP
using System.Security.Cryptography;
#endif

using KeePassLib.Cryptography;
using KeePassLib.Resources;
using KeePassLib.Security;
using KeePassLib.Utility;

namespace KeePassLib.Keys
{
  /// <summary>
  /// A user key depending on the currently logged on Windows user account.
  /// </summary>
  public sealed class KcpUserAccount : IUserKey
  {
    private ProtectedBinary m_pbKeyData = null;

    // Constant initialization vector (unique for KeePass)
    private static readonly byte[] m_pbEntropy = new byte[]{
            0xDE, 0x13, 0x5B, 0x5F, 0x18, 0xA3, 0x46, 0x70,
            0xB2, 0x57, 0x24, 0x29, 0x69, 0x88, 0x98, 0xE6
        };

    private const string UserKeyFileName = "ProtectedUserKey.bin";

    /// <summary>
    /// Get key data. Querying this property is fast (it returns a
    /// reference to a cached <c>ProtectedBinary</c> object).
    /// If no key data is available, <c>null</c> is returned.
    /// </summary>
    public ProtectedBinary KeyData
    {
      get { return m_pbKeyData; }
    }

    public uint GetMinKdbxVersion()
    {
      return 0;
    }

    /// <summary>
    /// Construct a user account key.
    /// </summary>
    public KcpUserAccount()
    {
      throw new NotSupportedException("DataProtection not supported on MonoForAndroid!");
    }

    // public void Clear()
    // {
    //	m_pbKeyData = null;
    // }

    private static byte[] LoadUserKey(bool bShowWarning)
    {
      byte[] pbKey = null;

#if !KeePassLibSD
      try
      {
        throw new NotSupportedException("DataProtection not supported on MonoForAndroid!");
      }
      catch (Exception exLoad)
      {
        if (bShowWarning) MessageService.ShowWarning(exLoad);

        pbKey = null;
      }
#endif

      return pbKey;
    }

    private static byte[] CreateUserKey()
    {
      byte[] pbKey = null;

#if !KeePassLibSD
      try
      {
        throw new NotSupportedException("DataProtection not supported on MonoForAndroid!");
      }
      catch (Exception) { pbKey = null; }
#endif

      return pbKey;
    }
  }
}
